Purposes of Invention
This invention relates to several improved automatic control systems for (a) machines compressing or pumping liquid, gaseous and slurry mediums and for (b) the networks and control elements which connect these compressing or pumping machines with either the sources or the users of the liquid, gaseous or slurry mediums. This invention relates for example, to the compressing or pumping stations and the related pipelines used to transport natural gas, oil, gasoline, water, etc. over various distances and the related network of pipeline and control elements; to compressors and compressing stations producing compressed air for ventilation and for pneumatic mechanisms and the related network of pipeline and control elements; to compressors or pumping stations compressing various gases, liquids or slurries in chemical or metallurgical plants and to the related network of pipeline and control elements and so on.
For the purposes of this invention the following terms are defined.
Compressing means -- a single compressing or pumping machine of any kind or a group of such machines.
Compressing station -- two, or more than two, compressing or pumping machines in a group.
Fluid -- a gaseous, liquid or slurry medium.
Source -- a technological unit which supplies liquid, gas or slurry medium to a compressing means. This may be, for example, a well head, an accumulator, another compressing or pumping station, a chemical process unit, etc. Several closely connected sources may be treated as one source.
User -- technological unit which receives, stores or processes the liquid, gas, or slurry, from a compressing means and fluidly connected to that means. This may be, for example, an accumulator of any kind, another compressing means, a chemical process unit, a pneumatic machine, etc. Several closely connected users may be treated as one user.
Many other well known terms of art used herein are defined in "Process Measurement and Control Terminology" copyrighted in 1970 by the Process Measurement and Control Section of the Scientific Apparatus Makers Association, 370 Lexington Avenue, New York, N.Y. 10017, which is incorporated herein by reference.
The main purposes to be achieved by the described automatic control systems of compressing means, the related pipeline network and control elements connecting them to the sources or users of fluid are:
(1) To maintain the required pressure either just before the users or just after the sources so as to minimize the compressing energy required; PA1 (2) Or to increase the process efficiency of the source or user such as the conversion efficiency of a chemical or other process, or to improve product quality in a manufacturing or conversion process. PA1 (3) Or to divide the load between the compressing units so as to compress the fluid with the reduced use of energy. PA1 (4) Or by improved automatic control of compressing stations to improve protection of the compressing units from dangerous levels of operation.